Since 2005, the US real estate market has crashed 35% whilst during the period, rents have risen dramatically.
Even US house builders have started specifically building rental properties.
There are several reasons:
A lack of funds. Buyers cannot afford the 20% deposit required for mortgages.
and they also fear:
Falling prices - why buy something that will be worth less in the future.
Being stuck with a home they cannot sell
Losing their job
Rising interest rates and the impact this will have on prices.
All of these fears are alleviated by renting.